Le 07/07/2023 à 03:31, Benjamin Gray a écrit :
> The KCOV handler __sanitizer_cov_trace_pc() uses the PACA, so initialise
> the PACA first. This fixes a hang during boot when KASAN and KCOV are
> both enabled, where the coverage tracer in kasan_early_init() tries to
> access a field of the (currently null) PACA.
mm/kasan/Makefile has KCOV_INSTRUMENT := n
Should we add the same in arch/powerpc/mm/kasan/Makefile to be consistent ?
>
> Signed-off-by: Benjamin Gray
>
> ---
>
> I tried annotating kasan_early_init() with 'notrace', but it still
> seemed to hang. It would also be less robust, because kasan_early_init()
> may in future call generic code that should keep coverage.
> ---
> arch/powerpc/kernel/head_64.S | 3 ---
> arch/powerpc/kernel/setup_64.c | 4
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index f132d8704263..21a78a849ca8 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -1004,9 +1004,6 @@ start_here_multiplatform:
>* and SLB setup before we turn on relocation.
>*/
>
> -#ifdef CONFIG_KASAN
> - bl CFUNC(kasan_early_init)
> -#endif
> /* Restore parameters passed from prom_init/kexec */
> mr r3,r31
> LOAD_REG_ADDR(r12, DOTSYM(early_setup))
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 246201d0d879..a3f5decbc041 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -369,6 +369,10 @@ void __init early_setup(unsigned long dt_ptr)
>
> /* printk is now safe to use --- */
>
> +#ifdef CONFIG_KASAN
> + kasan_early_init();
> +#endif
Don't #ifdef
In arch/powerpc/include/asm/kasan.h add a stub for kasan_early_init()
just like already done for kasan_init(), kasan_mmu_init() and
kasan_late_init().
> +
> if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && (mfmsr() & MSR_HV))
> enable_machine_check();
>
